1. Field of the Invention
The present invention relates to a feed drive mechanism, and more particularly to a feed drive mechanism having a connecting assembly.
2. Related Art
Currently, relevant products produced in the semiconductor industry, panel industry, biochip industry, and other industries have developed towards a new trend of being light, thin, short, and small, for example, micro-pores, micro-channels, V-shaped channels, shaped holes, and other elements with fine features, and the sizes thereof are mostly between several micrometers and hundreds of micrometers, such that a feeding accuracy of a feeding mechanism of a table for manufacturing such products must be improved accordingly, so as to meet the hyperfine processing demands.
FIGS. 1 and 2 are schematic views of a feed drive mechanism in the prior art. A conventional feed drive mechanism 10 is installed on a processing machinery frame 20, and two guide rails 21 spaced apart from each other and a movable base 22 connected to the feed drive mechanism 10 are disposed on the processing machinery frame 20. The movable base 22 may be disposed on the guide rails 21 in a movable relation, and may be moved reciprocally relative to the processing machinery frame 20.
Referring to FIGS. 1 and 2, the conventional feed drive mechanism 10 includes a bearing tailstock 11, a lead screw 12, a screw nut seat 13, a lead screw nut 14, a connecting plate 15, and a motor 16. The bearing tailstock 11 is fixed on the processing machinery frame 20. One end of the lead screw 12 is disposed on the bearing tailstock 11, and the other end thereof is connected to the motor 16, in which a disposing direction of the lead screw 12 is parallel to the guide rails 21. The screw nut seat 13 is sleeved on the lead screw 12 and combined with the movable base 22. The lead screw nut 14 is disposed in the screw nut seat 13 and sleeved on the lead screw 12. One end of the lead screw nut 14 is exposed out of the screw nut seat 13. The connecting plate 15 is sleeved on the lead screw 12 and combined and fixed with the screw nut seat 13 and the lead screw nut 14. When driving the lead screw 12 to rotate, the motor 16 drives the screw nut seat 13 and the movable base 22 together to reciprocally move towards a direction parallel to the guide rails 21, so as to achieve an accurate positioning function.
During the assembling process, the conventional feed drive mechanism unavoidably produces an assembly accuracy error, so that the feed drive mechanism cannot achieve a high assembling accuracy. For example, a micro-feed stick-slip phenomenon occurs due to a poor parallelism between the lead screw and the guide rails, a dead weight droop occurs due to an excessively large length of the lead screw, and other assembly errors may exist. As a result, a positioning accuracy of the feed drive mechanism cannot approach the ideal level, thereby seriously affecting the accuracy in the processing dimension. The connecting plate is disposed, which aims at repairing a sealing degree between the lead screw nut and the screw nut seat, instead of achieving the high accuracy and modifying the feeding errors for the feed drive mechanism.
During the operating process of the feed drive mechanism, balls (not shown) disposed inside the feed drive mechanism freely roll between the lead screw nut and the lead screw. Due to the high speed friction, the temperature of the lead screw nut and the lead screw quickly rises, and the parts of the feed drive mechanism are deformed due to the excessively high temperature, thereby resulting in a poor positioning accuracy.
In order to solve the heat error problem of the feed drive mechanism to relieve the influence of the temperature variation on the accuracy of the feed drive mechanism, in U.S. Pat. No. 6,817,260 and Taiwan Patent No. 1287073, a technical solution of designing a cooling device in a lead screw nut of a feed drive mechanism is disclosed, thereby lowering the high temperature generated when the feed drive mechanism is operated.
However, a cooling device of the conventional feed drive mechanism is directly designed on the lead screw nut, which has the following problems.
1. In order to meet the high rigidity and high accuracy requirements for the feed drive mechanism, the processing accuracy requirements for the lead screw nut must be increased accordingly, thereby resulting in a high manufacturing cost, complicated manufacturing procedures, and a long manufacturing time.
2. The cooling device is additionally disposed within the lead screw nut, such that a size and a type of the lead screw nut originally as the specification product are forced to be changed, such that the lead screw nut has a poor interchangeability, and it is inconvenient for subsequent maintenance.
3. The lead screw nut designed with the cooling device still cannot meet the high assembly accuracy requirements for the feed drive mechanism.